Transparent Display Device

ABSTRACT

A transparent display device for providing only a viewer located at the front with an image is disclosed. The transparent display device comprises a substrate provided with a first subpixel, a second subpixel and a third subpixel, a first electrode provided in each of the first subpixel, the second subpixel and the third subpixel on the substrate, a light emitting layer provided on the first electrode, a second electrode provided on the light emitting layer, an upper color filter provided over the second electrode, a lower color conversion layer provided between the substrate and the first electrode, and a lower color filter provided between the substrate and the lower color conversion layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Republic of Korea PatentApplication No. 10-2018-0173462 filed on Dec. 31, 2018, which is herebyincorporated by reference in their entirety.

BACKGROUND Technical Field

The present disclosure relates to a transparent display device fordisplaying an image.

Description of the Related Art

With the advancement of the information age, a demand for a transparentdisplay device for displaying an image has been increased in variousforms. Therefore, various display devices such as liquid crystal display(LCD) devices, plasma display panel (PDP) devices, and organic lightemitting display (OLED) devices have been used.

Recent, studies for transparent display devices for allowing a user tolook at objects or background arranged on a rear surface of a displaydevice are actively ongoing. The transparent display devices haveadvantages in space availability, interior, and design and may beapplied to various fields. The transparent display devices may embody aninformation recognition function, an information processing function,and an information display function by using a transparent electronicdevice, thereby solving the spatial limitation and visual limitation ofthe existing electronic devices. For example, the transparent displaydevices may be applied to windows of buildings or vehicles and thus maybe embodied as a smart window which allows the background to be seen ordisplays an image.

The transparent display device has a non-transmissive area and atransmissive area, and transmits light to the transmissive area. Thetransparent display device may display an image on the transmissivearea. In this case, when a viewer located in front of the transparentdisplay device views the image, a third party located behind thetransparent display device may also view the image. At this time,problems may occur in that information may be released to the thirdparty through the image displayed on the transparent display device andprivacy is not ensured.

SUMMARY

The present disclosure has been made in view of the above problems, andit is an object of the present disclosure to provide a transparentdisplay device for providing only a viewer located at the front with animage.

In addition to the objects of the present disclosure as mentioned above,additional objects and features of the present disclosure will beclearly understood by those skilled in the art from the followingdescription of the present disclosure.

In accordance with an aspect of the present disclosure, the above andother objects can be accomplished by the provision of a transparentdisplay device comprising a substrate provided with a first subpixel, asecond subpixel and a third subpixel, a first electrode provided in eachof the first subpixel, the second subpixel and the third subpixel on thesubstrate, a light emitting layer provided on the first electrode, asecond electrode provided on the light emitting layer, an upper colorfilter provided on the second electrode, a lower color conversion layerprovided between the substrate and the first electrode, and a lowercolor filter provided between the substrate and the lower colorconversion layer.

According to the present disclosure, the lower conversion layer isprovided between the substrate and the first electrode, whereby lightemitted from the light emitting layer is shielded from progressing tothe substrate. For this reason, the transparent display device accordingto the present invention cannot allow a viewer located behind thetransparent display device to view an image.

Also, the present disclosure embodies a transparent display device thatallows a viewer located in front of the transparent display device toview an object or a background arranged on a rear surface as well as animage which is displayed. The present invention allows a viewer locatedin front of the transparent display device to view an image displayed ona transparent display and at the same time allows a third party locatedbehind the transparent display device not to view the image. Therefore,the present invention may prevent information from being released to thethird party through the image displayed on the transparent displaydevice and make sure of privacy.

In addition to the effects of the present disclosure as mentioned above,additional advantages and features of the present disclosure will beclearly understood by those skilled in the art from the abovedescription of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view illustrating a transparent display deviceaccording to one embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along line I-I′ of FIG. 2according to one embodiment of the present disclosure;

FIG. 3 is a cross-sectional view illustrating an example of a firstelectrode and a light emitting layer in a display device according toone embodiment of the present disclosure;

FIG. 4 is a cross-sectional view according to a modified embodiment ofFIG. 2;

FIG. 5 is a cross-sectional view according to another modifiedembodiment of FIG. 2;

FIG. 6 is a cross-sectional view according to still another modifiedembodiment of FIG. 2; and

FIG. 7 is a cross-sectional view according to further still anothermodified embodiment of FIG. 2.

DETAILED DESCRIPTION

Advantages and features of the present disclosure, and implementationmethods thereof will be clarified through following embodimentsdescribed with reference to the accompanying drawings. The presentdisclosure may, however, be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present disclosureto those skilled in the art. Further, the present disclosure is onlydefined by scopes of claims.

A shape, a size, a ratio, an angle, and a number disclosed in thedrawings for describing embodiments of the present disclosure are merelyan example, and thus, the present disclosure is not limited to theillustrated details. Like reference numerals refer to like elementsthroughout the specification. In the following description, when thedetailed description of the relevant known function or configuration isdetermined to unnecessarily obscure the important point of the presentdisclosure, the detailed description will be omitted. In a case where‘comprise’, ‘have’, and ‘include’ described in the present specificationare used, another part may be added unless ‘only˜’ is used. The terms ofa singular form may include plural forms unless referred to thecontrary.

In construing an element, the element is construed as including an errorrange although there is no explicit description.

In describing a position relationship, for example, when the positionrelationship is described as ‘upon˜’, ‘above˜’, ‘below˜’, and ‘nextto˜’, one or more portions may be arranged between two other portionsunless ‘just’ or ‘direct’ is used.

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure.

In describing elements of the present disclosure, the terms “first”,“second”, etc. may be used. These terms are intended to identify thecorresponding elements from the other elements, and basis, order, ornumber of the corresponding elements are not limited by these terms. Theexpression that an element is “connected” or “coupled” to anotherelement should be understood that the element may directly be connectedor coupled to another element but may directly be connected or coupledto another element unless specially mentioned, or a third element may beinterposed between the corresponding elements.

Features of various embodiments of the present disclosure may bepartially or overall coupled to or combined with each other, and may bevariously inter-operated with each other and driven technically as thoseskilled in the art can sufficiently understand. The embodiments of thepresent disclosure may be carried out independently from each other, ormay be carried out together in co-dependent relationship.

Hereinafter, an example of a transparent display device according to thepresent disclosure will be described in detail with reference to theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

FIG. 1 is a perspective view illustrating a transparent display deviceaccording to one embodiment of the present disclosure, FIG. 2 is across-sectional view taken along line I-I′ of FIG. 2, FIG. 3 is across-sectional view illustrating an example of a first electrode and alight emitting layer in a display device according to one embodiment ofthe present disclosure, FIG. 4 is a cross-sectional view according to amodified embodiment of FIG. 2, FIG. 5 is a cross-sectional viewaccording to another modified embodiment of FIG. 2, and FIG. 6 is across-sectional view according to still another modified embodiment ofFIG. 2. FIG. 7 is a cross-sectional view according to further stillanother modified embodiment of FIG. 2.

Referring to FIGS. 1 to 3, the transparent display device 100 accordingto one embodiment of the present disclosure comprises a substrate 110, acircuit element layer 200, a lower conversion layer 300, a firstelectrode 400, a bank 445, a light emitting layer 500, a secondelectrode 600, an encapsulation layer 700, and an upper conversion layer800.

The substrate 110 may be made of, but not limited to, glass or plastic.The substrate 110 may be made of a semiconductor material such assilicon wafer. The substrate 110 may be made of a transparent materialto transmit externally incident light.

A first subpixel P1, a second subpixel P2, and a third subpixel P3 areprovided over the substrate 110. The first subpixel P1 may emit redlight, the second subpixel P2 may emit green light, and the thirdsubpixel P3 may emit blue light, but these subpixels are not limited tothis example. For example, an arrangement sequence of the subpixel P1,P2 and P3 may be changed in various ways.

The circuit element layer 200 is provided over the substrate 110.

The circuit element layer 200 includes a circuit element comprisingvarious types of signal lines, a transistor and a capacitor. The circuitelement is provided for each of the subpixels P1, P2, and P3. The signallines may include gate lines, data lines, power lines and referencelines, and the transistor may include a switching thin film transistor,a driving thin film transistor TFT, and a sensing transistor.

The switching thin film transistor is switched in accordance with a gatesignal supplied to the gate line and serves to supply a data voltagesupplied from the data line to the driving thin film transistor TFT.

The driving thin film transistor TFT is switched in accordance with thedata voltage supplied from the switching thin film transistor togenerate a data current from a power source supplied from the power lineand serves to supply the generated data current to the first electrodes410, 420 and 430.

The sensing transistor serves to sense a threshold voltage deviation ofthe driving thin film transistor, which is a cause of image degradation,and supplies a current of the driving thin film transistor to thereference line in response to a sensing control signal supplied from thegate line or a separate sensing line.

The capacitor serves to maintain the data voltage supplied to thedriving thin film transistor TFT for one frame and is connected to eachof a gate terminal and a source terminal of the driving thin filmtransistor TFT.

An inter-layer dielectric film 215 is provided over the various signallines, the transistor and the capacitor to planarize an upper surface.

The inter-layer dielectric film 215 may be formed of, but not limitedto, an inorganic film, for example, a silicon oxide (SiOx) film, asilicon nitride (SiNx) film, or a multi-layered film of the SiOx filmand the SiNx film. The inter-layer dielectric film 215 may be formed ofan organic film, for example, acryl resin, epoxy resin, phenolic resin,polyamide resin, polyimide resin, etc. Alternatively, the inter-layerdielectric film 215 may be formed of a multi-layered film of at leastone inorganic film and at least one organic film.

The lower conversion layer 300 is provided over the circuit elementlayer 200, and shields light emitted from the light emitting layer 500from progressing to the substrate 110. To this end, the lower conversionlayer 300 includes a first lower conversion layer 310 made of a firstlower color filter 311, a second lower conversion layer 320 made of asecond lower color conversion layer 322 and a second lower color filter321, and a third lower conversion layer 330 made of a third lower colorconversion layer 332 and a third lower color filter 331.

The first lower conversion layer 310 is formed to be patterned on aposition corresponding to the first subpixel P1. Particularly, the firstlower conversion layer 310 may be arranged on a light emitting area EAof the first subpixel P1.

The first lower color filter 311 transmits light of a red wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a green wavelength range.The first lower color filter 311 may include a red dye.

In the first subpixel P1, light emitted from the light emitting layer500 may progress to a lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is partiallyshielded from progressing to the substrate 110 due to the first lowerconversion layer 310.

In detail, the first lower color filter 311 transmits light of a redwavelength range from the light emitted from the light emitting layer500, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a green wavelength range.As a result, only the light of the red wavelength range from the lightemitted from the light emitting layer 500, progressing to the substrate110 may pass through the substrate 110.

Meanwhile, the first lower color filter 311 transmits light of a redwavelength range from external light entering toward the substrate 110,and absorbs light of the other wavelength ranges, for example, light ofa blue wavelength range and light of a green wavelength range.Therefore, only the light of the red wavelength range from the externallight may enter the first upper color filter 811.

The second lower conversion layer 320 is formed to be patterned on aposition corresponding to the second subpixel P2. Particularly, thesecond lower conversion layer 320 may be arranged on a light emittingarea EA of the second subpixel P2.

The second lower color conversion layer 322 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The second lower color conversionlayer 322 absorbs light of a yellow wavelength range or light of a greenwavelength range and converts the corresponding light to light of a redwavelength range. The second lower color conversion layer 322 mayinclude red quantum dot particles.

The second lower color filter 321 transmits light of a green wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a red wavelength range.The second lower color filter 321 may include a green dye.

In the second subpixel P2, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is shielded fromprogressing to the substrate 110 due to the second lower conversionlayer 320.

In detail, the second lower color conversion layer 322 absorbs light ofa yellow wavelength range or light of a green wavelength range from thelight emitted from the light emitting layer 500 and converts thecorresponding light to light of the red wavelength range. Therefore, thelight of the blue wavelength range and the light of the red wavelengthrange remain as the light which has passed through the second lowercolor conversion layer 322. At this time, since the light of the greenwavelength range is absorbed by the second lower color conversion layer322, the light of the green wavelength range fails to pass through thesecond lower color conversion layer 322.

The second lower color filter 321 transmits the light of the greenwavelength range from the incident light from the second lower colorconversion layer 322, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the redwavelength range. Since the light of the blue wavelength range and thelight of the red wavelength range only pass through the second lowercolor conversion layer 322, the second lower color filter 321 fullyabsorbs the incident light from the second lower color conversion layer322.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the second lowerconversion layer 320.

Meanwhile, the second lower conversion layer 320 partially transmitsexternal light entering toward the substrate 110. In detail, the secondlower color filter 321 transmits light of the green wavelength rangefrom the external light entering toward the substrate 110, and absorbslight of the other wavelength ranges, for example, light of the bluewavelength range and light of the red wavelength range. The second lowercolor conversion layer 322 absorbs light of the green wavelength rangefrom the second lower color filter 321 and converts the correspondinglight to light of the red wavelength range. The second lower conversionlayer 320 may transmit only the light of the red wavelength range fromthe external light entering toward the substrate 110. Therefore, onlythe light of the red wavelength range from the external light may enterthe second upper color filter 821.

The third lower conversion layer 330 is formed to be patterned on aposition corresponding to the third subpixel P3. Particularly, the thirdlower conversion layer 330 may be arranged on a light emitting area EAof the third subpixel P3.

The third lower color conversion layer 332 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The third lower color conversionlayer 332 absorbs light of a blue wavelength range and converts thecorresponding light to light of a green wavelength range. The thirdlower color conversion layer 332 may include green quantum dotparticles.

The third lower color filter 331 transmits light of a blue wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a green wavelength range and light of a red wavelength range.The third lower color filter 331 may include a blue dye.

In the third subpixel P3, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is shielded fromprogressing to the substrate 110 due to the third lower conversion layer330.

In detail, the third lower color conversion layer 332 absorbs light of ablue wavelength range from the light emitted from the light emittinglayer 500 and converts the corresponding light to light of a greenwavelength range. Therefore, the light of the green wavelength range andthe light of the red wavelength range remain as the light which haspassed through the third lower color conversion layer 332. At this time,since the light of the blue wavelength range is absorbed by the thirdlower color conversion layer 332, the light of the blue wavelength rangefails to pass through the third lower color conversion layer 332.

The third lower color filter 331 transmits the light of the bluewavelength range from the incident light from the third lower colorconversion layer 332, and absorbs light of the other wavelength ranges,for example, light of the green wavelength range and light of the redwavelength range. Since the light of the green wavelength range and thelight of the red wavelength range only pass through the third lowercolor conversion layer 332, the third lower color filter 331 fullyabsorbs the incident light from the third lower color conversion layer332.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the third lowerconversion layer 330.

Meanwhile, the third lower conversion layer 330 partially transmitsexternal light entering toward the substrate 110. In detail, the thirdlower color filter 331 transmits light of the blue wavelength range fromthe external light entering toward the substrate 110, and absorbs lightof the other wavelength ranges, for example, light of the greenwavelength range and light of the red wavelength range. The third lowercolor conversion layer 332 absorbs light of the blue wavelength rangefrom the third lower color filter 331 and converts the correspondinglight to light of the green wavelength range. The third lower conversionlayer 330 may transmit only the light of the green wavelength range fromthe external light entering toward the substrate 110. Therefore, onlythe light of the green wavelength range from the external light mayenter a third upper color filter 831.

In the transparent display device 100 according to one embodiment of thepresent disclosure, the light emitted from the second subpixel P2 andthe light emitted from the third subpixel P3 fail to pass through thesubstrate 110. Also, in the transparent display device 100 according toone embodiment of the present disclosure, the light emitted from thefirst subpixel P1 fails to partially pass through the substrate 110.Therefore, in the transparent display device 100 according to oneembodiment of the present disclosure, a viewer cannot view a completeimage at the rear of the transparent display device.

A planarization film 340 is provided over the first lower conversionlayer 310, the second lower conversion layer 320, and the third lowerconversion layer 330 to planarize the first lower conversion layer 310,the second lower conversion layer 320, and the third lower conversionlayer 330.

The planarization film 340 may be formed of, but not limited to, aninorganic film, for example, a silicon oxide (SiOx) film, a siliconnitride (SiNx) film, or a multi-layered film of the SiOx film and theSiNx film. The planarization film 340 may be formed of an organic film,for example, acryl resin, epoxy resin, phenolic resin, polyamide resin,polyimide resin, etc. Alternatively, the planarization film 340 may beformed of a multi-layered film of at least one inorganic film and atleast one organic film.

A contact hole CH is provided in the circuit element layer 200 and thelower conversion layer 300 for each of the subpixels P1, P2, and P3,whereby a source terminal or a drain terminal of the driving thin filmtransistor TFT is exposed through the contact hole CH. The contact holeCH may be provided in a non-light emitting area NEA overlapped with thebank 445.

The first electrode 400 is formed to be patterned on the lowerconversion layer 300 for each of the subpixels P1, P2 and P3. One firstelectrode 410 is provided in the first subpixel P1, another firstelectrode 420 is provided in the second subpixel P2, and another firstelectrode 430 is provided in the third subpixel P3.

The first electrodes 410, 420, and 430 are each connected with acorresponding driving thin film transistor TFT provided in the circuitelement layer 200. In detail, the first electrodes 410, 420 and 430 areeach connected with the source terminal or the drain terminal of acorresponding driving thin film transistor TFT through the contact holeCH provided in the circuit element layer 200.

The first electrodes 410, 420, and 430 may be formed of a transparentconductive material (TCO) such as ITO and IZO, which can transmit light.The first electrodes 410, 420 and 430 may be anode electrodes.

The bank 445 is provided over the circuit element layer 200 to overlay apart of edges of the first electrodes 410, 420, and 430, whereby lightemitting efficiency may be prevented from being deteriorated due to acurrent concentrated on the ends of the first electrodes 410, 420, and430.

The bank 445 is provided among the subpixels P1, P2, and P3 in a matrixarrangement and defines a light emitting area EA in each of the first,second, and third subpixels P1, P2, and P3. That is, an opening areawhere the bank 445 is not provided in each of the subpixels P1, P2, andP3 becomes a light emitting area EA. On the other hand, an area wherethe bank 445 is provided in each of the subpixels P1, P2 and P3 is anon-light emitting area NEA.

The bank 445 may be made of a relatively thin inorganic insulating filmor a relatively thick organic insulating film. Also, the bank 445 mayinclude a material that can absorb light, for example, a black dye. Thatis, the bank 445 may be a black bank. The bank 445 may absorb lightprogressing to adjacent subpixels P1, P2, and P3, among the lightemitted from the light emitting layer 500. Therefore, color mixture maybe prevented from being generated among the adjacent subpixels P1, P2,and P3.

If the bank 445 is a black bank, the bank 445 may define a transmissivearea TA in each of the plurality of subpixels P1, P2 and P3. That is,the exposed area of the first electrodes 410, 420, and 430, in which thebank 445 is not provided in each of the subpixels P1, P2, and P3, may bea transmissive area TA, and the area where the bank 445 is provided maybe a non-transmissive area NTA (e.g., a non-emission area NEA).

The light emitting layer 500 is provided over the first electrodes 410,420, and 430. The light emitting layer 500 may be provided over the bank445. That is, the light emitting layer 500 is also provided in each ofthe subpixels P1, P2 and P3 and a boundary area among the subpixels P1,P2 and P3.

The light emitting layer 500 may be a white light emitting layer. Inthis case, the light emitting layer 500 may be a common layer commonlyprovided in the subpixels P1, P2 and P3.

The light emitting layer 500, as shown in FIG. 3, includes a first stackstack1 for emitting light of a first color, a second stack stack2 foremitting light of a second color, and a charge generating layer CGLprovided between the first stack and the second stack.

The first stack stack1 is provided over the first electrodes 410, 420and 430. The first stack stack1 may be formed of, but not limited to, adeposited structure of a hole injecting layer HIL, a hole transportinglayer HTL, a first light emitting layer EML1 for emitting light of afirst color, and an electron transporting layer ETL, which are depositedin due order.

The first light emitting layer EML1 may be at least one, but not limitedto, a red light emitting layer for emitting red light, a green lightemitting layer for emitting green light, a blue light emitting layer foremitting blue light, or a yellow light emitting layer for emittingyellow light.

The second stack stack2 is provided over the charge generating layerCGL. The second stack stack2 may be formed of, but not limited to, adeposited structure of a hole transporting layer HTL, a second lightemitting layer EML2 for emitting light of a second color, an electrontransporting layer ETL, and an electron injecting layer EIL, which aredeposited in due order. The second light emitting layer EML2 may be atleast one, but not limited to, a red light emitting layer for emittingred light, a green light emitting layer for emitting green light, a bluelight emitting layer for emitting blue light, or a yellow light emittinglayer for emitting yellow light.

However, the second light emitting layer EML2 may emit light of a colordifferent from that of the first light emitting layer EML1. For example,the first light emitting layer EML1 may be a blue light emitting layerfor emitting blue light, and the second light emitting layer EML2 may bea yellow light emitting layer for emitting yellow light. For anotherexample, the first light emitting layer EML1 may be a blue lightemitting layer for emitting blue light, and the second light emittinglayer EML2 may be a red light emitting layer for emitting red light anda green light emitting layer for emitting green light.

The charge generating layer CGL may be provided in a deposited structureof an N type charge generating layer for providing electrons to thefirst stack Stack1 and a P type charge generating layer for providingholes to the second stack Stack2.

The second electrode 600 is provided over the light emitting layer 500.In the same manner as the light emitting layer 500, the second electrode600 is also provided in each of the subpixels P1, P2 and P3 and theboundary area among the subpixels P1, P2, and P3. That is, the secondelectrode 600 may also be provided above the bank 445.

The second electrode 600 may be formed of a transparent conductivematerial (TCO) such as ITO and IZO, which can transmit light. The secondelectrode may be a cathode electrode.

The encapsulation layer 700 is provided over the second electrode 600 toprevent external water from being permeated into the light emittinglayer 500. The encapsulation layer 700 may be made of, but not limitedto, an inorganic insulating material or a structure in which aninorganic material and an organic material are deposited alternately.

Although not shown in FIG. 3, a capping layer may additionally beprovided between the second electrode 600 and the encapsulation layer700.

The upper conversion layer 800 is provided over the encapsulation layer700. The upper conversion layer 800 may allow each of the subpixels P1,P2, and P3 to emit only light of a specific wavelength range byabsorbing light of a predetermined wavelength range from the lightemitted from the light emitting layer 500. The upper conversion layer800 may be formed of a material known in the art, such as a dye, resinor dielectric, which absorbs light of a specific wavelength range.

The upper conversion layer 800 is formed to be patterned for each of thesubpixels P1, P2, and P3. In detail, the upper conversion layer 800includes a first upper color filter 811 provided to correspond to thefirst subpixel P1, a second upper color filter 821 provided tocorrespond to the second subpixel P2, and a third upper color filter 831provided to correspond to the third subpixel P3.

The first upper color filter 811 passes through light of the redwavelength range from the light emitted from the light emitting layer500, and absorbs light of the other wavelength ranges, for example,light of the green wavelength range and light of the blue wavelengthrange. The first upper color filter 811 may include a red dye.

Also, the first upper color filter 811 transmits the incident light ofthe red wavelength range from the first lower conversion layer 310.Therefore, a transmissive area TA may be provided in the first subpixelP1. A viewer located at the front may view an object or backgroundlocated at the rear through the first subpixel P1.

The second upper color filter 821 passes through light of the greenwavelength range from the light emitted from the light emitting layer500, and absorbs light of the other wavelength ranges, for example,light of the red wavelength range and light of the blue wavelengthrange. The second upper color filter 821 may include a green dye.Meanwhile, the second upper color filter 821 absorbs the incident lightof the red wavelength range from the second lower conversion layer 320.

The third upper color filter 831 passes through light of the bluewavelength range from the light emitted from the light emitting layer500, and absorbs light of the other wavelength ranges, for example,light of the red wavelength range and light of the green wavelengthrange. The third upper color filter 831 may include a blue dye.Meanwhile, the third upper color filter 831 absorbs the incident lightof the green wavelength range from the third lower conversion layer 330.

Although FIG. 2 shows that the different lower conversion layers 310,320, and 330 are respectively provided in the subpixels P1, P2 and P3,the present disclosure is not limited to the example of FIG. 2.

In another embodiment, the lower conversion layer 300, as shown in FIG.4, may include only the second lower conversion layer 320 comprised ofthe second lower color conversion layer 322 and the second lower colorfilter 321.

In detail, the second lower conversion layer 320 is formed to bepatterned on a position corresponding to each of the subpixels P1, P2,and P3. Particularly, the second lower conversion layer 320 may bearranged on a light emitting area EA of each of the subpixels P1, P2,and P3.

The second lower color conversion layer 322 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The second lower color conversionlayer 322 absorbs light of a yellow wavelength range or light of a greenwavelength range and converts the corresponding light to light of a redwavelength range. The second lower color conversion layer 322 mayinclude red quantum dot particles.

The second lower color filter 321 transmits light of a green wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a red wavelength range.The second lower color filter 321 may include a green dye.

In each of the subpixels P1, P2, and P3, light emitted from the lightemitting layer 500 may progress to the lower portion on which thesubstrate 110 is arranged. The light progressing to the lower portion isshielded from progressing to the substrate 110 due to the second lowerconversion layer 320.

The second lower color conversion layer 322 absorbs light of a yellowwavelength range or light of a green wavelength range from the lightemitted from the light emitting layer 500 and converts the correspondinglight to light of the red wavelength range. Therefore, the light of theblue wavelength range and the light of the red wavelength range remainas the light which has passed through the second lower color conversionlayer 322. At this time, since the light of the green wavelength rangeis absorbed by the second lower color conversion layer 322, the light ofthe green wavelength range fails to pass through the second lower colorconversion layer 322.

The second lower color filter 321 transmits the light of the greenwavelength range from the incident light from the second lower colorconversion layer 322, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the redwavelength range. Since the light of the blue wavelength range and thelight of the red wavelength range only pass through the second lowercolor conversion layer 322, the second lower color filter 321 fullyabsorbs the incident light from the second lower color conversion layer322.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the second lowerconversion layer 320.

Meanwhile, the second lower conversion layer 320 partially transmitsexternal light entering toward the substrate 110. In detail, the secondlower color filter 321 transmits light of the green wavelength rangefrom the external light entering toward the substrate 110, and absorbslight of the other wavelength ranges, for example, light of the bluewavelength range and light of the red wavelength range. The second lowercolor conversion layer 322 absorbs the incident light of the greenwavelength range from the second lower color filter 321 and converts thecorresponding light to light of the red wavelength range. Therefore,only the light of the red wavelength range from the external light mayenter the first upper color filter 811, the second upper color filter821 and the third upper color filter 831.

The first upper color filter 811 transmits the incident light of the redwavelength range from the second lower conversion layer 320. Therefore,a transmissive area TA may be provided in the first subpixel P1. Aviewer located at the front may view an object or background located atthe rear through the first subpixel P1.

Meanwhile, the second upper color filter 821 and the third upper colorfilter 831 absorb incident light of a red wavelength range from thesecond lower conversion layer 320.

In the transparent display device 100 according to another embodiment ofthe present disclosure, the light emitted from each of the subpixels P1,P2, and P3 does not pass through the substrate 110 due to the secondlower conversion layer 320. Therefore, in the transparent display device100 according to another embodiment of the present invention, a viewercannot view an image at the rear.

Meanwhile, unlike FIG. 4, in still another embodiment, the lowerconversion layer 300 may include only the third lower conversion layer330 comprised of the third lower color conversion layer 332 and thethird lower color filter 331.

In detail, the third lower conversion layer 330 is formed to bepatterned on a position corresponding to each of the subpixels P1, P2,and P3. Particularly, the third lower conversion layer 330 may bearranged on a light emitting area EA of each of the subpixels P1, P2 andP3.

The third lower color conversion layer 332 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The third lower color conversionlayer 332 absorbs light of a blue wavelength range and converts thecorresponding light to light of a green wavelength range. The thirdlower color conversion layer 332 may include green quantum dotparticles.

The third lower color filter 331 transmits light of a blue wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a green wavelength range and light of a red wavelength range.The third lower color filter 331 may include a blue dye.

In each of the subpixels P1, P2, and P3, light emitted from the lightemitting layer 500 may progress to the lower portion on which thesubstrate 110 is arranged. The light progressing to the lower portion isshielded from progressing to the substrate 110 due to the third lowerconversion layer 330.

In detail, the third lower color conversion layer 332 absorbs light of ablue wavelength range from the light emitted from the light emittinglayer 500 and converts the corresponding light to light of a greenwavelength range. Therefore, the light of the green wavelength range andthe light of the red wavelength range remain as the light which haspassed through the third lower color conversion layer 332. At this time,since the light of the blue wavelength range is absorbed by the thirdlower color conversion layer 332, the light of the blue wavelength rangefails to pass through the third lower color conversion layer 332.

The third lower color filter 331 transmits the light of the bluewavelength range from the incident light from the third lower colorconversion layer 332, and absorbs light of the other wavelength ranges,for example, light of the green wavelength range and light of the redwavelength range. Since the light of the green wavelength range and thelight of the red wavelength range only pass through the third lowercolor conversion layer 332, the third lower color filter 331 fullyabsorbs the incident light from the third lower color conversion layer332.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the third lowerconversion layer 330.

Meanwhile, the third lower conversion layer 330 partially transmitsexternal light entering toward the substrate 110. In detail, the thirdlower color filter 331 transmits light of the blue wavelength range fromthe external light entering toward the substrate 110, and absorbs lightof the other wavelength ranges, for example, light of the greenwavelength range and light of the red wavelength range. The third lowercolor conversion layer 332 absorbs the incident light of the bluewavelength range from the third lower color filter 331 and converts thecorresponding light to light of the green wavelength range. Therefore,only the light of the green wavelength range from the external light mayenter the first upper color filter 811, the second upper color filter821 and the third upper color filter 831.

The second upper color filter 821 transmits the incident light of thegreen wavelength range from the third lower conversion layer 330.Therefore, a transmissive area TA may be provided in the second subpixelP2. A viewer located at the front may view an object or backgroundlocated at the rear through the second subpixel P2.

Meanwhile, the first upper color filter 811 and the third upper colorfilter 831 absorb incident light of a green wavelength range from thethird lower conversion layer 330.

In the transparent display device 100 according to still anotherembodiment of the present invention, the light emitted from each of thesubpixels P1, P2, and P3 does not pass through the substrate 110 due tothe third lower conversion layer 330. Therefore, in the transparentdisplay device 100 according to still another embodiment of the presentinvention, a viewer cannot view an image at the rear.

In further still another embodiment, the lower conversion layer 300, asshown in FIG. 5, may include the second lower conversion layer 320comprised of the second lower color conversion layer 322 and the secondlower color filter 321, and the third lower conversion layer 330comprised of the third lower color conversion layer 332 and the thirdlower color filter 331.

Any one of the second lower conversion layer 320 and the third lowerconversion layer 330 may be provided in each of the subpixels P1, P2 andP3.

In detail, the second lower conversion layer 320 is formed to bepatterned on a position corresponding to each of the first subpixel P1and the second subpixel P2. Particularly, the second lower conversionlayer 320 may be arranged on a light emitting area EA of each of thefirst subpixel P1 and the second subpixel P2.

The second lower color conversion layer 322 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The second lower color conversionlayer 322 absorbs light of a yellow wavelength range or light of a greenwavelength range and converts the corresponding light to light of a redwavelength range. The second lower color conversion layer 322 mayinclude red quantum dot particles.

The second lower color filter 321 transmits light of a green wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a red wavelength range.The second lower color filter 321 may include a green dye.

In each of the first subpixel P1 and the second subpixel P2, lightemitted from the light emitting layer 500 may progress to the lowerportion on which the substrate 110 is arranged. The light progressing tothe lower portion is shielded from progressing to the substrate 110 dueto the second lower conversion layer 320.

In detail, the second lower color conversion layer 322 absorbs light ofa yellow wavelength range or light of a green wavelength range from thelight emitted from the light emitting layer 500 and converts thecorresponding light to light of the red wavelength range. Therefore, thelight of the blue wavelength range and the light of the red wavelengthrange remain as the light which has passed through the second lowercolor conversion layer 322. At this time, since the light of the greenwavelength range is absorbed by the second lower color conversion layer322, the light of the green wavelength range fails to pass through thesecond lower color conversion layer 322.

The second lower color filter 321 transmits the light of the greenwavelength range from the incident light from the second lower colorconversion layer 322, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the redwavelength range. Since the light of the blue wavelength range and thelight of the red wavelength range only pass through the second lowercolor conversion layer 322, the second lower color filter 321 fullyabsorbs the incident light from the second lower color conversion layer322.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the second lowerconversion layer 320.

Meanwhile, the second lower conversion layer 320 partially transmitsexternal light entering toward the substrate 110. In detail, the secondlower color filter 321 transmits light of the green wavelength rangefrom the external light entering toward the substrate 110, and absorbslight of the other wavelength ranges, for example, light of the bluewavelength range and light of the red wavelength range. The second lowercolor conversion layer 322 absorbs the incident light of the greenwavelength range from the second lower color filter 321 and converts thecorresponding light to light of the red wavelength range. The secondlower conversion layer 320 may transmit only the light of the redwavelength range from the external light entering toward the substrate110. Therefore, only the light of the red wavelength range from theexternal light may enter the first upper color filter 811 and the secondupper color filter 821.

The first upper color filter 811 transmits the incident light of the redwavelength range from the second lower conversion layer 320. Therefore,a transmissive area TA may be provided in the first subpixel P1. Aviewer located at the front may view an object or background located atthe rear through the first subpixel P1. Meanwhile, the second uppercolor filter 821 absorbs incident light of the red wavelength range fromthe second lower conversion layer 320.

The third lower conversion layer 330 is formed to be patterned on aposition corresponding to the third subpixel P3. Particularly, the thirdlower conversion layer 330 may be arranged on a light emitting area EAof the third subpixel P3.

The third lower color conversion layer 332 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The third lower color conversionlayer 332 absorbs light of a blue wavelength range and converts thecorresponding light to light of a green wavelength range. The thirdlower color conversion layer 332 may include green quantum dotparticles.

The third lower color filter 331 transmits light of a blue wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a green wavelength range and light of a red wavelength range.The third lower color filter 331 may include a blue dye.

In the third subpixel P3, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is shielded fromprogressing to the substrate 110 due to the third lower conversion layer330.

In detail, the third lower color conversion layer 332 absorbs light of ablue wavelength range from the light emitted from the light emittinglayer 500 and converts the corresponding light to light of a greenwavelength range. Therefore, the light of the green wavelength range andthe light of the red wavelength range remain as the light which haspassed through the third lower color conversion layer 332. At this time,since the light of the blue wavelength range is absorbed by the thirdlower color conversion layer 332, the light of the blue wavelength rangefails to pass through the third lower color conversion layer 332.

The third lower color filter 331 transmits the light of the bluewavelength range from the incident light from the third lower colorconversion layer 332, and absorbs light of the other wavelength ranges,for example, light of the green wavelength range and light of the redwavelength range. Since the light of the green wavelength range and thelight of the red wavelength range only pass through the third lowercolor conversion layer 332, the third lower color filter 331 fullyabsorbs the incident light from the third lower color conversion layer332.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the third lowerconversion layer 330.

Meanwhile, the third lower conversion layer 330 partially transmitsexternal light entering toward the substrate 110. In detail, the thirdlower color filter 331 transmits light of the blue wavelength range fromthe external light entering toward the substrate 110, and absorbs lightof the other wavelength ranges, for example, light of the greenwavelength range and light of the red wavelength range. The third lowercolor conversion layer 332 absorbs the incident light of the bluewavelength range from the third lower color filter 331 and converts thecorresponding light to light of the green wavelength range. Therefore,only the light of the green wavelength range from the external light mayenter the third upper color filter 831.

The third upper color filter 831 absorbs the incident light of the greenwavelength range from the third lower conversion layer 330.

In the transparent display device 100 according to further still anotherembodiment of the present disclosure, the light emitted from each of thesubpixels P1, P2, and P3 does not pass through the substrate 110 due tothe second lower conversion layer 320 and the third lower conversionlayer 330. Therefore, in the transparent display device 100 according tofurther still another embodiment of the present disclosure, a viewercannot view an image at the rear.

Meanwhile, in further still another embodiment, the lower conversionlayer 300, as shown in FIG. 6, may include the second lower conversionlayer 320 comprised of the second lower color conversion layer 322 andthe second lower color filter 321, the third lower conversion layer 330comprised of the third lower color conversion layer 332 and the thirdlower color filter 331, and a fourth lower conversion layer 340comprised of a fourth lower color filter 341.

In detail, the second lower conversion layer 320 is formed to bepatterned on a position corresponding to the first subpixel P1.Particularly, the second lower conversion layer 320 may be arranged on alight emitting area EA of the first subpixel P1.

The second lower color conversion layer 322 may be a downward conversionlayer. The second lower color conversion layer 322 absorbs light of ayellow wavelength range or light of a green wavelength range andconverts the corresponding light to light of a red wavelength range. Thesecond lower color conversion layer 322 may include red quantum dotparticles.

The second lower color filter 321 transmits light of a green wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a blue wavelength range and light of a red wavelength range.The second lower color filter 321 may include a green dye.

In the first subpixel P1, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is shielded fromprogressing to the substrate 110 due to the second lower conversionlayer 320.

In detail, the second lower color conversion layer 322 absorbs light ofa yellow wavelength range or light of a green wavelength range from thelight emitted from the light emitting layer 500 and converts thecorresponding light to light of the red wavelength range. Therefore, thelight of the blue wavelength range and the light of the red wavelengthrange remain as the light which has passed through the second lowercolor conversion layer 322. At this time, since the light of the greenwavelength range is absorbed by the second lower color conversion layer322, the light of the green wavelength range fails to pass through thesecond lower color conversion layer 322.

The second lower color filter 321 transmits the light of the greenwavelength range from the incident light from the second lower colorconversion layer 322, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the redwavelength range. Since the light of the blue wavelength range and thelight of the red wavelength range only pass through the second lowercolor conversion layer 322, the second lower color filter 321 fullyabsorbs the incident light from the second lower color conversion layer322.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the second lowerconversion layer 320.

Meanwhile, the second lower conversion layer 320 partially transmitsexternal light entering toward the substrate 110. In detail, the secondlower color filter 321 transmits light of the green wavelength rangefrom the external light entering toward the substrate 110, and absorbslight of the other wavelength ranges, for example, light of the bluewavelength range and light of the red wavelength range. The second lowercolor conversion layer 322 absorbs the incident light of the greenwavelength range from the second lower color filter 321 and converts thecorresponding light to light of the red wavelength range. The secondlower conversion layer 320 may transmit only the light of the redwavelength range from the external light entering toward the substrate110. Therefore, only the light of the red wavelength range from theexternal light may enter the first upper color filter 811.

The first upper color filter 811 transmits the incident light of the redwavelength range from the second lower conversion layer 320. Therefore,a transmissive area TA may be provided in the first subpixel P1. Aviewer located at the front may view an object or background located atthe rear through the first subpixel P1.

The third lower conversion layer 330 is formed to be patterned on aposition corresponding to the second subpixel P2. Particularly, thethird lower conversion layer 330 may be arranged on a light emittingarea EA of the second subpixel P2.

The third lower color conversion layer 332 may be a downward conversionlayer. The downward conversion layer may emit light having low energy byabsorbing light having high energy. The third lower color conversionlayer 332 absorbs light of a blue wavelength range and converts thecorresponding light to light of a green wavelength range. The thirdlower color conversion layer 332 may include green quantum dotparticles.

The third lower color filter 331 transmits light of a blue wavelengthrange, and absorbs light of the other wavelength ranges, for example,light of a green wavelength range and light of a red wavelength range.The third lower color filter 331 may include a blue dye.

In the third subpixel P3, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is shielded fromprogressing to the substrate 110 due to the third lower conversion layer330.

In detail, the third lower color conversion layer 332 absorbs light of ablue wavelength range from the light emitted from the light emittinglayer 500 and converts the corresponding light to light of a greenwavelength range. Therefore, the light of the green wavelength range andthe light of the red wavelength range remain as the light which haspassed through the third lower color conversion layer 332. At this time,since the light of the blue wavelength range is absorbed by the thirdlower color conversion layer 332, the light of the blue wavelength rangefails to pass through the third lower color conversion layer 332.

The third lower color filter 331 transmits the light of the bluewavelength range from the incident light from the third lower colorconversion layer 332, and absorbs light of the other wavelength ranges,for example, light of the green wavelength range and light of the redwavelength range. Since the light of the green wavelength range and thelight of the red wavelength range only pass through the third lowercolor conversion layer 332, the third lower color filter 331 fullyabsorbs the incident light from the third lower color conversion layer332.

As a result, the light emitted from the light emitting layer 500,progressing to the substrate 110 is fully absorbed by the third lowerconversion layer 330.

Meanwhile, the third lower conversion layer 330 partially transmitsexternal light entering toward the substrate 110. In detail, the thirdlower color filter 331 transmits light of the blue wavelength range fromthe external light entering toward the substrate 110, and absorbs lightof the other wavelength ranges, for example, light of the greenwavelength range and light of the red wavelength range. The third lowercolor conversion layer 332 absorbs the incident light of the bluewavelength range from the third lower color filter 331 and converts thecorresponding light to light of the green wavelength range. The thirdlower conversion layer 330 may transmit only the light of the greenwavelength range from the external light entering toward the substrate110. Therefore, only the light of the green wavelength range from theexternal light may enter the second upper color filter 821.

The second upper color filter 821 transmits the incident light of thegreen wavelength range from the third lower conversion layer 330.Therefore, a transmissive area TA may be provided in the second subpixelP2. A viewer located at the front may view an object or backgroundlocated at the rear through the second subpixel P2.

The fourth lower conversion layer 340 is formed to be patterned on aposition corresponding to the third subpixel P3. Particularly, thefourth lower conversion layer 340 may be arranged on a light emittingarea EA of the third subpixel P3. The fourth lower color filter 341transmits light of a blue wavelength range, and absorbs light of theother wavelength ranges, for example, light of a green wavelength rangeand light of a red wavelength range. The fourth lower color filter 341may include a blue dye.

In the third subpixel P3, light emitted from the light emitting layer500 may progress to the lower portion on which the substrate 110 isarranged. The light progressing to the lower portion is partiallyshielded from progressing to the substrate 110 due to the fourth lowerconversion layer 340.

In detail, the fourth lower color filter 341 transmits the light of theblue wavelength range from the incident light from light emitting layer500, and absorbs light of the other wavelength ranges, for example,light of the green wavelength range and light of the red wavelengthrange. As a result, only the light of the blue wavelength range in thelight emitted from the light emitting layer 500, progressing to thesubstrate 110 may pass through the substrate 110.

Meanwhile, the fourth lower color filter 341 transmits only the light ofthe blue wavelength range from the external light entering toward thesubstrate 110, and absorbs light of the other wavelength ranges, forexample, light of the red wavelength range and light of the greenwavelength range. Therefore, only the light of the blue wavelength rangefrom the external light may enter the third upper color filter 831.

The third upper color filter 831 transmits the incident light of theblue wavelength range from the fourth lower conversion layer 340.Therefore, a transmissive area TA may be provided in the third subpixelP3. A viewer located at the front may view an object or backgroundlocated at the rear through the third subpixel P3.

In the transparent display device 100 according to further still anotherembodiment of the present disclosure, the light emitted from the firstsubpixel P1 and the second subpixel P2 does not pass through thesubstrate 110 due to the second lower conversion layer 320 and the thirdlower conversion layer 330. Also, in the transparent display device 100according to further still another embodiment of the present disclosure,the light emitted from the third subpixel P3 does not partially passthrough the substrate 110. Therefore, in the transparent display device100 according to further still another embodiment of the presentinvention, a viewer cannot view a complete image at the rear.

Also, in the transparent display device 100 according to further stillanother embodiment of the present disclosure, since the transmissivearea TA is provided in all of the subpixels P1, P2 and P3, transparencyof the device may be improved.

Meanwhile, although FIG. 2 shows that the upper conversion layer 800does not include a color conversion layer, the upper conversion layer800 is not limited to the example of FIG. 2.

In another embodiment, the upper conversion layer 800, as shown in FIG.7, may include a first upper conversion layer 810 comprised of a firstupper color conversion layer 812 and a first upper color filter 811, asecond upper conversion layer 820 comprise of a second upper colorconversion layer 822 and a second upper color filter 821, and a thirdupper conversion layer 830 comprised of a third upper color conversionlayer 832 and a third upper color filter 831.

In detail, the first upper conversion layer 810 may be formed to bepatterned on a position corresponding to the first subpixel P1.

The first upper color conversion layer 812 may be a downward conversionlayer. The first upper color conversion layer 812 may absorb light of ayellow wavelength range or light of a green wavelength range from lightemitted from the light emitting layer 500 and convert the correspondinglight to light of a red wavelength range. The first upper colorconversion layer 812 may include red quantum dot particles.

The first upper color filter 811 transmits light of the red wavelengthrange and absorbs light of the other wavelength ranges, for example,light of the blue wavelength range and light of the green wavelengthrange. The first upper color filter 811 may include a red dye.

In the first subpixel P1, the light emitted from the light emittinglayer 500 may progress to the upper portion on which the encapsulationlayer 700 is arranged. The first upper color conversion layer 812absorbs light of the yellow wavelength range or light of the greenwavelength range from the light emitted from the light emitting layer500 and converts the corresponding light to light of the red wavelengthrange. Therefore, the light of the blue wavelength range and the lightof the red wavelength range remain as the light that has passed throughthe first upper color conversion layer 812.

The first upper color filter 811 transmits the light of the redwavelength range from the incident light from the first upper colorconversion layer 812, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the greenwavelength range. As a result, the first upper color filter 811transmits only the light of the red wavelength range.

The second upper conversion layer 820 may be formed to be patterned on aposition corresponding to the second subpixel P2.

The second upper color conversion layer 822 may be a downward conversionlayer. The second upper color conversion layer 822 may absorb light ofthe blue wavelength range from the light emitted from the light emittinglayer 500 and convert the corresponding light to the light of the greenwavelength range. The second upper color conversion layer 822 mayinclude green quantum dot particles.

The second upper color filter 821 transmits light of the greenwavelength range and absorbs light of the other wavelength ranges, forexample, light of the blue wavelength range and light of the redwavelength range. The second upper color filter 821 may include a greendye.

In the second subpixel P2, the light emitted from the light emittinglayer 500 may progress to the upper portion on which the encapsulationlayer 700 is arranged. The second upper color conversion layer 822absorbs light of the blue wavelength range from the light emitted fromthe light emitting layer 500 and converts the corresponding light tolight of the green wavelength range. Therefore, the light of the greenwavelength range and the light of the red wavelength range remain as thelight that has passed through the second upper color conversion layer822.

The second upper color filter 821 transmits the light of the greenwavelength range from the incident light from the second upper colorconversion layer 822, and absorbs light of the other wavelength ranges,for example, light of the blue wavelength range and light of the redwavelength range. As a result, the second upper color filter 821transmits only the light of the green wavelength range.

The third upper conversion layer 830 may be formed to be patterned on aposition corresponding to the third subpixel P3.

The third upper color conversion layer 832 may be a downward conversionlayer. The third upper color conversion layer 832 may absorb light of awavelength range shorter than the blue wavelength range from the lightemitted from the light emitting layer 500 and convert the correspondinglight to the light of the blue wavelength range. The third upper colorconversion layer 832 may include blue quantum dot particles.

The third upper color filter 831 transmits light of the blue wavelengthrange and absorbs light of the other wavelength ranges, for example,light of the green wavelength range and light of the red wavelengthrange. The third upper color filter 831 may include a blue dye.

In the third subpixel P3, the light emitted from the light emittinglayer 500 may progress to the upper portion on which the encapsulationlayer 700 is arranged. The third upper color conversion layer 832absorbs light of the wavelength range shorter than the blue wavelengthrange from the light emitted from the light emitting layer 500 andconverts the corresponding light to light of the blue wavelength range.Therefore, the light of the blue wavelength range, the light of thegreen wavelength range and the light of the red wavelength range remainas the light that has passed through the third upper color conversionlayer 832.

The third upper color filter 831 transmits the light of the bluewavelength range from the incident light from the third upper colorconversion layer 832, and absorbs light of the other wavelength ranges,for example, light of the green wavelength range and light of the redwavelength range. As a result, the third upper color filter 831transmits only the light of the blue wavelength range.

In the transparent display device 100 according to further still anotherembodiment of the present disclosure, the color conversion layers 812,822 and 832 may further be provided over the upper conversion layer 800,whereby efficiency of light emitted from each of the subpixels P1, P2,and P3 may be improved.

Meanwhile, although not described in detail, the upper conversion layer800 shown in FIG. 7 is also applicable to the embodiments shown in FIGS.4 to 6.

It will be apparent to those skilled in the art that the presentdisclosure described above is not limited by the above-describedembodiments and the accompanying drawings and that varioussubstitutions, modifications, and variations can be made in the presentdisclosure without departing from the spirit or scope of thedisclosures. Consequently, the scope of the present disclosure isdefined by the accompanying claims, and it is intended that allvariations or modifications derived from the meaning, scope, andequivalent concept of the claims fall within the scope of the presentdisclosure.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

What is claimed is:
 1. A transparent display device comprising: asubstrate provided with a first subpixel, a second subpixel, and a thirdsubpixel; first electrodes provided in each of the first subpixel, thesecond subpixel, and the third subpixel over the substrate; a lightemitting layer provided over the first electrodes; a second electrodeprovided over the light emitting layer; an upper color filter providedover the second electrode; a lower color conversion layer providedbetween the substrate and the first electrodes; and a lower color filterprovided between the substrate and the lower color conversion layer. 2.The transparent display device of claim 1, wherein the upper colorfilter includes a first upper color filter for transmitting light of ared wavelength range and absorbing light of other wavelength rangesexcept the red wavelength range, a second upper color filter fortransmitting light of a green wavelength range and absorbing light ofother wavelength ranges except the green wavelength range, and a thirdupper color filter for transmitting light of a blue wavelength range andabsorbing light of other wavelength ranges except the blue wavelengthrange.
 3. The transparent display device of claim 2, wherein the lowercolor conversion layer includes a first lower color conversion layer forabsorbing the light of the blue wavelength range and converting thecorresponding light to the light of the green wavelength range, and asecond lower color conversion layer for absorbing light of a yellowwavelength range or the light of the green wavelength range andconverting the corresponding light to the light of the red wavelengthrange.
 4. The transparent display device of claim 3, wherein the lowercolor filter includes a first lower color filter for transmitting thelight of the blue wavelength range and absorbing the light of the otherwavelength ranges except the blue wavelength range, and a second lowercolor filter for transmitting the light of the green wavelength rangeand absorbing the light of the other wavelength ranges except the greenwavelength range, and wherein the first lower color conversion layer isprovided over the first lower color filter, and the second lower colorconversion layer is provided over the second lower color filter.
 5. Thetransparent display device of claim 4, wherein the second upper colorfilter, the first lower color conversion layer, and the first lowercolor filter are provided in any one of the first subpixel, the secondsubpixel, and the third subpixel.
 6. The transparent display device ofclaim 4, wherein the first upper color filter, the second lower colorconversion layer, and the second lower color filter are provided in anyone of the first subpixel, the second subpixel, and the third subpixel.7. The transparent display device of claim 2, further comprising anupper color conversion layer provided between the second electrode andthe upper color filter.
 8. The transparent display device of claim 7,wherein the upper color conversion layer includes a first upper colorconversion layer for absorbing the light of the blue wavelength rangeand converting the corresponding light to the light of the greenwavelength range, and a second upper color conversion layer forabsorbing the light of a yellow wavelength range and converting thecorresponding light to the light of the red wavelength range, andwherein the first upper color conversion layer is provided below thesecond upper color filter, and the second upper color conversion layeris provided below the first upper color filter.
 9. The transparentdisplay device of claim 8, wherein the upper color conversion layerfurther includes a third upper color conversion layer for absorbinglight of a wavelength range shorter than the blue wavelength range andconverting the corresponding light to the light of the blue wavelengthrange, and the third upper color conversion layer is provided below thethird upper color filter.
 10. The transparent display device of claim 1,wherein the first electrodes and the second electrode are made of atransparent metal material.
 11. The transparent display device of claim1, wherein the light emitted from the light emitting layer, progressingto the substrate is shielded by the lower color conversion layer and thelower color filter.
 12. The transparent display device of claim 1,further comprising a bank that partially exposes each of the firstelectrodes while overlaying a part of an end of each of the firstelectrodes.
 13. The transparent display device of claim 12, wherein thebank includes a material for absorbing light.
 14. A transparent displaydevice, comprising: a substrate provided with a first subpixel and asecond subpixel; first electrodes provided in each of the first subpixeland the second subpixel over the substrate; a light emitting layerprovided over the first electrodes; a second electrode provided over thelight emitting layer; an upper conversion layer provided over the secondelectrode; and a lower conversion layer provided between the substrateand the first electrodes, wherein a part of light emitted from the lightemitting layer is shielded from progressing to the substrate by thelower conversion layer.
 15. The transparent display device of claim 14,wherein the upper conversion layer comprising a first upper color filterfor transmitting light of a first color and absorbing light of the othercolor except the first color in the first subpixel, and a second uppercolor filter for transmitting light of a second color and absorbinglight of the other color except the second color in the second subpixel,and wherein the lower conversion layer comprising a first lower colorconversion layer for absorbing light of the second color and convertinglight of the second color into light of a wavelength longer than that oflight of the second color; and a first lower color filter providedbetween the substrate and the first lower color conversion layer, fortransmitting light of the second color and absorbing light of the othercolor except the second color.
 16. The transparent display device ofclaim 15, wherein the first lower color conversion layer and the firstlower color filter are provided in any one of the first subpixel and thesecond subpixel, such that the light emitted from the light emittinglayer, progressing to the substrate is shielded by the first lower colorconversion layer and the first lower color filter.
 17. The transparentdisplay device of claim 16, wherein the first lower color conversionlayer absorbs light of the second color and converts light of the secondcolor into light of the first color, and wherein the first lower colorconversion layer and the first lower color filter are provided in thefirst subpixel, such that the first subpixel becomes a transmissive areaallowing an external light entering the substrate to pass through. 18.The transparent display device of claim 16, wherein the lower conversionlayer further comprises a second lower color filter provided in thefirst subpixel, for transmitting light of the first color and absorbinglight of the other color except the first color, and wherein the firstlower color conversion layer and the first lower color filter areprovided in the second subpixel.
 19. The transparent display device ofclaim 17, wherein the lower conversion layer further comprises a secondlower color filter provided in the second subpixel, for transmittinglight of the second color and absorbing light of the other color exceptthe second color.
 20. The transparent display device of claim 15,wherein the upper conversion layer further comprises at least one of: afirst upper color conversion layer provided between the second electrodeand the first upper color filter, for absorbing light of wavelengthshorter than that of light of the first color, and converting thecorresponding light into light of the first color; and a second uppercolor conversion layer provided between the second electrode and thesecond upper color filter, for absorbing light of wavelength shorterthan that of light of the second color, and converting the correspondinglight into light of the second color.